At least ten kinds of hawks and two species of eagles migrate north over Lancaster County, Pennsylvania during March and April. They are going to their breeding territories farther north where they will spend the summer raising young. They can be spotted, along with common loons, geese and other species of birds, if one looks to the sky with binoculars from most any point of land. But these raptors are scattered across the landscape, so time and much patience is required to spot them in the sky. The twelve species are sharp-shinned and Cooper's hawks, merlins, peregrines and American kestrels, northern harriers, red-tailed, red-shouldered and broad-winged hawks, ospreys, bald eagles and golden eagles. But the most common raptor migrants noticed powering or soaring north through here during March and April are bald eagles, red-tails, sharpies, kestrels, ospreys and broad-wings in that arbitrary order of being spotted during those months.
Bald eagles are one of the first raptors to migrate north through Lancaster County, as early as February, and into March. Many of them winter in Lancaster County, but one knows they started their migrations when their winter gatherings disperse. Those majestic migrants can be spotted anywhere soaring on high, but are most likely seen near waterways and impoundments where they sometimes stop to catch fish. But they also scavenge dead farm animals disposed of in cropland. And we can see those magnificent birds feeding in those fields before they continue their flight north. The white heads and tails of adult balds gleam from high in the sky, making their identification unmistakable. Some balds raise young here in Lancaster County, particularly along the Susquehanna River and in farmland where they scavenged dead chickens and turkeys all winter.
Red-tails are the most abundant of all diurnal raptors wintering in this area, and the most commonly spotted spring migrant here, mostly during March. And many pairs of this buteo hawk rear offspring in stick nurseries in cropland and suburbs in this county, feeding the young a variety of rodents and other prey. The reddish-orange tails of the adults identify this species. Immature birds have brown tails until they are three years old.
The large red-tails do a lot of soaring on the wind, which saves them much energy. They gain altitude by seeking rising columns of warmed air (thermals) that spiral them higher and higher, without expending energy beating their wings.
The diminutive sharp-shinned hawks do a lot of alternate flapping and soaring in speedy, head-long flight. These little accipitor hawks are about the size of blue jays and are fast on the wing to catch their prey of small birds. Their size, shape, speed, squared-off tail and manner of flight identify this species in the sky. I also know when sharpies are on migration during March into April because they show up at bird feeders to prey on small birds in places where they had not been all winter. They are suddenly at the feeders and just as suddenly gone.
American kestrels, too, are swift on the wing. This species is robin-sized with pointed, swept-back wings for fast flight. This is a farmland hawk and occasionally, in April, several of them on migration can be spotted hovering together, by chance, over a field or pasture as they watch for invertebrates on the ground to catch and eat before flying farther north.
Kestrels are colorful little members of the falcon family of hawks. Males are pale-orange and brown with black and gray markings. Females are more brown with black markings, a plumage that camouflages them. Some kestrels raise young in tree cavities or boxes erected especially for them here in Lancaster County farmland.
The large, stately ospreys sail over this area from the end of March through much of April. This species of fish-eating hawk doesn't winter here at all. But a few pairs nest along the Susquehanna River, while the rest of the ospreys spotted here are migrants heading farther north. Ospreys are dark above and white below with a dark, horizontal stripe through each side of the white head.
Broad-wings are the most exciting of migrant hawks here in spring. They come through here in spectacular, silent flocks on high around the middle of April, with a peak of migration about the 20th of that month. Though they may be high in the sky, they can be observed circling in a thermal or floating north in groups or long lines with the aid of binoculars. Many broadies nest in local forests, while others continue farther north to raise youngsters.
Broad-wings are small buteos and are so-named because they have broad wings for the size of their bodies. These are not power fliers, but their wide wings catch every breeze or thermal that lifts them high with little effort on their part.
Hawks migrating without expending much energy is good because predatory creatures expend a lot of time and energy catching their elusive prey. So any conservation of energy on the hawks' parts
allows them to travel farther and longer between meals, without their health and stamina suffering.
By the end of April, north-bound hawk migration is completed. But that migration is not obvious; one must look for it with binoculars. But it is thrilling when noticed.
No comments:
Post a Comment